This invention relates to pulse detonation engines, and more particularly, to multiple detonation initiators for pulse detonation combustors.
In recent years, efforts to address the need of a combination of combustion systems to obtain a wide range of flight speeds for aircraft have led to the development of pulse detonation combustors, which can be used on aircraft engines (as well as other applications). When used on aircraft engines, pulse detonation engines aid in increasing the available flight speed range of an aircraft engine while reducing the need for a combination of combustion systems.
Pulse detonation combustors create high pressure and temperature detonation waves by combusting a mixture of gas (typically air) and a hydrocarbon fuel. The detonation waves exit the pulse detonation combustor tube as pulses, thus providing thrust. Because of the nature of the operation of pulse detonation combustors (i.e. a series of discrete detonations), there is a limit to the frequencies at which conventional simple tube pulse detonation combustors can operate. This is especially true of tube pulse detonation combustors which use a mixture of air and a hydrocarbon fuel as the detonable component. One of the limitations of hydrocarbon-air mixtures is the relatively long time for run-up to detonation at ambient conditions, with a weak detonation initiation.
However, for a number of reasons, it is desirable to operate pulse detonation combustors at as high a frequency as possible. First, the operation of a pulse detonation combustor at a high frequency minimizes the excitation of the mechanical structure of an engine, or other structure surrounding or supporting the pulse detonation combustor. Operation at low frequencies tends to inflict resonant damage to supporting structure or engines. Second, operation at higher frequencies minimizes the pressure and velocity fluctuations flowing to upstream parts of the flow system, including: inlets, compressors and diffusers.
The present invention addresses the above issues.